Submitted by rbserver, also found by HE1M, bin2chen, unforgiven, cccz, KingNFT, and stealthyz
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L689-L750 
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L762-L810 
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L287-L294
Calling the following Trading._handleOpenFees function does not approve the GovNFT contract for spending any of the Trading contracts _tigAsset balance, which is unlike calling the Trading._handleCloseFees function below that executes IStable(_tigAsset).approve(address(gov), type(uint).max). Due to this lack of approval, when calling the Trading._handleOpenFees function without the Trading._handleCloseFees function being called for the same _tigAsset beforehand, the GovNFT.distribute functions execution of IERC20(_tigAsset).transferFrom(_msgSender(), address(this), _amount) in the try...catch... block will not transfer any _tigAsset amount as the trades DAO fees to the GovNFT contract. 
In this case, although the Governance NFT holder, whose NFT was minted before the Trading._handleOpenFees function is called, deserves the rewards from the DAO fees generated by the trade, this holder does not have any pending rewards after such Trading._handleOpenFees function call because none of the DAO fees were transferred to the GovNFT contract. Hence, this Governance NFT holder loses the rewards that she or he is entitled to.
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L689-L750
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L762-L810
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L287-L294
Functions like Trading.initiateMarketOrder further call the Trading._handleOpenFees function so this POC uses the Trading.initiateMarketOrder function.
Please add the following test in the Signature verification describe block in test\07.Trading.js. This test will pass to demonstrate the described scenario. Please see the comments in this test for more details.
Furthermore, as a suggested mitigation, please add IStable(_tigAsset).approve(address(gov), type(uint).max); in the _handleOpenFees function as follows in line 749 of contracts\Trading.sol.
Then, as a comparison, the following test can be added in the Signature verification describe block in test\07.Trading.js. This test will pass to demonstrate that the Governance NFT holders pending rewards is no longer 0 after implementing the suggested mitigation. Please see the comments in this test for more details.
VS Code
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L749 can be updated to the following code.
TriHaz (Tigris Trade) confirmed, but disagreed with severity and commented:
Alex the Entreprenerd (judge) decreased severity to Medium and commented:
GainsGoblin (Tigris Trade) resolved:
